Conventional microphone porting typically includes a round sound hole opening that is typically 1-2 millimeters deep and a cavity (104), as shown in FIG. 1, numeral 100, that is typically 1-2 millimeters deep. The diameter of the sound hole opening (102) is determined by a desired overall frequency response curve which depends on the size of the sound hole opening (102), the volume of the cavity (104), and the characteristics of a microphone transducer (106) that is placed at the bottom of the cavity (104). When a handset having a microphone with a round opening and a cavity is utilized under windy conditions, wind-induced noise may decrease microphone performance in the form of fluttering background noise which can render the voice sound unintelligible.
Wind-induced noise arises from the hydrodynamic instability of the flow of air over the cavity (104) sound hole opening (102). As shown in FIGS. 2-3, numerals 200 and 300, the wind flow (202) across an opening (206) produces separation vortices (204) that produce a hyperbolic wind velocity profile (302) that is unstable.
Thus, there is a need for a method and device for minimizing wind-induced noise in microphones.